During the season of my senior year of football I suffered two concussions within the same week. After hearing more about concussions (on multiple doctor visits) I became interested as to just what makes them so dangerous. When two concussions occur within a short amount of time there is a possibility of Second Impact Syndrome (SIS) which generally leads to death or being reduced to a vegetative state. I found an interesting article (http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2672291/ ) which explains why SIS is so dangerous
The article states that after a primary concussion the body tries to auto regulate the amount of damage to the brain by reducing the amount of blood flow to the brain. This is obviously problematic due to the fact that we know the brain needs plenty of oxygen and other essential items as well as getting rid of the waste products in order for the brain to operate at maximum performance. With an already limited amount of blood flow to the brain this makes the second concussion even more dangerous now that the brain has lost its ability to auto regulate. The article then states that even a non-lethal blow to the head after the initial concussion is sufficient to hinder the brains ability to manage intracranial pressure which leads to a subdural hematoma resulting in death. This can happen in a matter of minutes following the second impact!
I find it very interesting as to how the brains limits blood flow in order to try and minimize the amount of damage. Then again I can’t think of a better way to try and keep the amount of swelling down.